An emperor colony located near Britain's Halley Research Station. Using a satellite mosaic map created during the International Polar Year that was partly funded by the National Science Foundation, British scientists identified 10 new colonies.

The poop on penguins

Penguin guano stains, visible from space, have helped British scientists locate emperor penguin breeding colonies in Antarctica. The researchers used satellite images downloaded from the Landsat Image Mosaic of Antarctica (LIMA) for the survey.

In a study published this week in the journal Global Ecology and Biogeography, scientists from BAS describe how they used the LIMA satellite images to survey sea ice around 90 percent of Antarctica’s coast to search for emperor penguin colonies. The survey identified a total of 38, which included 10 new colonies. Of the previously known colonies, six had re-located and six were not found.

“We can’t see actual penguins on the satellite maps because the resolution isn’t good enough,” explained BAS mapping expert Peter Fretwell in a news release. “But during the breeding season, the birds stay at a colony for eight months. The ice gets pretty dirty, and it’s the guano stains that we can see.”

Emperor penguins spend a large part of their lives at sea. During the Antarctic winter, when temperatures drop to minus 50 degrees Celsius, they return to their colonies to breed on sea ice, but this is a time when it is most difficult for scientists to monitor them.

The LIMA map is a realistic, nearly cloudless satellite view of the continent stitched together from nearly 1,100 images captured by the NASA-built Landsat 7 satellite mainly from 1999 to 2001. The Landsat Program is a series of Earth-observing satellite missions jointly managed by NASA and the USGS. The first Landsat satellite was launched in 1972.